1. Field of the Invention
This invention relates to a trigger operated fluid delivery system for dispensing two fluids. In particular, the invention relates to a trigger operated fluid dispenser that allows a user to add a secondary fluid to the spray of a primary fluid.
2. Description of the Related Art
It is often desirable to simultaneously dispense two types of fluid from two fluid containers of a trigger operated sprayer assembly. For example, when two fluids to be dispensed contain some active ingredients that are incompatible when these ingredients are mixed together in a single solution, it is desirable to contain the two fluids in separate compartments and then mix and dispense both fluids simultaneously as a single fluid. Also, it may be desirable to separately store a first liquid carrier and a second concentrate fluid and then mix and dispense both fluids simultaneously as a single fluid. The first primary fluid might be water or a dilute primary light-duty cleaner, and the secondary fluid may be a concentrate that when combined in small amounts with the primary fluid yields a new cleaning formulation. Alternatively, one container might hold a first fluid with an active ingredient, which the second fluid in the second container would activate. Non-limiting examples of such pairs of fluids could be a cleaning composition and a bleach, or a pair of stain removing compositions, one an aqueous composition and the other a high-solvent level enzyme containing composition. Whatever the pair of fluids, they are intended to be dispensed simultaneously and in a fixed ratio to each other, the ratio being set by the design of the trigger operated fluid delivery system itself.
There are many examples in the art of manually activated pumps for spraying two liquids simultaneously. For example, U.S. Pat. No. 5,560,545 describes a fluid dispenser that employs separate dip tubes drawing from separate bottle compartments with the two liquids to be dispensed being drawn by a single piston to a mixing chamber prior to spraying through a nozzle. U.S. Pat. No. 5,535,950 discloses a trigger actuated fluid dispenser for simultaneously dispensing two fluids separately stored in separate fluid compartments of a container wherein the dispenser includes side-by-side pump cylinders receiving side-by-side pump pistons reciprocable simultaneously during each pressure stroke applied by a single trigger lever for separately and simultaneously pumping the disparate fluids along separate discharge paths. The disclosures of these patents and of all other publications referred to herein are incorporated by reference as if fully set forth herein.
It has been recognized in the art that dispensers such as those in U.S. Pat. Nos. 5,560,545 and 5,535,950 do have disadvantages when attempting to deliver a concentrate from a secondary container. When the secondary container's contents are a concentrate, the dip tubes and other extensive fluid transfer means of dispensers such as those in U.S. Pat. Nos. 5,560,545 and 5,535,950 may require that inconvenient amounts of the concentrate be expended simply to prime the pump or otherwise fill the system. Furthermore, dispensers such as those in U.S. Pat. Nos. 5,560,545 and 5,535,950 do not provide for the convenient replacement of one secondary container by another secondary container, without disturbing the primary container.
The manually operable dispensing pump of U.S. Pat. No. 5,964,377 overcomes the aforementioned disadvantages of dispensers such as those in U.S. Pat. Nos. 5,560,545 and 5,535,950. U.S. Pat. No. 5,964,377 discloses a dispensing pump with a secondary fluid container that is attachable by secondary attachment means directly to the sprayer body at a location remote from the primary fluid container. The secondary container has an outlet that provides immediate communication between the secondary container and the sprayer mechanism so that contents of the secondary container can pass immediately into a mixing chamber in the sprayer body to be mixed with primary fluid pumped from the primary container. The secondary container is detachable and replaceable such that convenient recharging of the device with a refill secondary container or the exchange of one secondary container for another secondary container is possible.
It has also been recognized in the art that dispensers such as those in U.S. Pat. Nos. 5,560,545 and 5,535,950 do have problems with container venting and the proper maintenance of flow rates from the primary and secondary container. These problems have been addressed by the sprayer assembly of U.S. Pat. No. 5,819,987 which provides an apparatus for dispensing multiple fluids from nested containers, while simultaneously venting the fluid containers. The sprayer assembly includes a first container for containing a first fluid, a second container, nested within the first container, for containing a second fluid, and a manually operable pump for pumping fluid from the containers to dispense a mixture of the fluids from the apparatus. The pump includes a pump actuator, a reciprocating fluid conduit which reciprocates upon actuation and deactuation of the pump actuator, and a discharge nozzle for dispensing the mixture of the fluids from the apparatus upon actuation of the pump. The apparatus also includes a mixing chamber for mixing the first and second fluids drawn from the first and second containers, respectively, a fluid transfer conduit for withdrawing fluid from the first container into the mixing chamber and a fluid transfer mechanism for withdrawing fluid from the second container into the mixing chamber.
While the devices of U.S. Pat. Nos. 5,819,987 and 5,964,377 have solved various problems with manually activated pumps for spraying two liquids simultaneously, there is still a need for alternative fluid delivery systems for mixing and dispensing two separate fluids.